Airspring assembly

ABSTRACT

An improved airspring assembly that includes a collapsible support member disposed within the pressurizable chamber of an airspring having a flexible sidewall. The support member is configured such that it extends and collapses along a longitudinal axis of the chamber responsive to pressurization and depressurization of the chamber, respectively. The support member also is configured such that it retains a substantially rigid outer perimeter, thereby restricting movement of the chamber&#39;s flexible sidewall toward the longitudinal axis when the chamber is depressurized. The support member also is configured such that it does not interfere with the full stroke of the airspring.

This application claims priority to and is a continuation-in-part of application Ser. No. 11/257,413 filed Oct. 24, 2005, which is a divisional application of and claims priority to U.S. patent application Ser. No. 10/317,648 that issued as U.S. Pat. No. 6,957,806 on Oct. 25, 2005, each of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention is related generally to airspring suspension systems for vehicles, and, more particularly, to an improved airspring suspension system that reduces the potential for damage to the air bag portion of the airspring due to pinching of the bag portion when air pressure is released.

II. Background

In general, an airspring is a pneumatic spring configured as a column of gas confined within a container. The pressure of the confined gas, and not the structure of the container, acts as the force medium of the spring. A wide variety of sizes and configurations of airsprings are available, including sleeve-type airsprings, bellows-type airsprings, convoluted-type airsprings, rolling lobe airsprings, etc. Such airsprings commonly are used in both vehicular and industrial applications. Vehicular applications include suspension systems for automobiles, light trucks, semi-tractors and trailers, buses, trains, recreational vehicles, etc., while industrial applications include use in vibration isolation systems.

Airsprings, regardless of their size and configuration, share many common elements. In general, an airspring includes a flexible, sleeve-like member made of fabric-reinforced rubber that defines the sidewall of an inflatable container. Each end of the flexible member is closed by an enclosure element, such as a bead plate which is attached to the flexible member by crimping. The uppermost enclosure element typically also includes air supply components and mounting elements (e.g., studs, blind nuts, brackets, pins, etc.) to couple the airspring to the vehicle structure. The lowermost enclosure element also typically includes mounting elements to couple the airspring to the vehicle axle.

In vehicular applications, airspring suspensions offer many advantages over conventional steel spring-type suspension arrangements, particularly with respect to driver discomfort, cargo damage, and vehicle deterioration. For example, the principle drawback of steel spring suspension systems is their degree of stiffness. Because steel springs must be designed to handle the vehicle's maximum load, the suspension system often is too stiff to provide adequate, or any, shock absorption at light or no-load conditions. Airspring suspension systems, on the other hand, can accommodate load changes simply by adjusting the amount of air pressure in the inflatable container. Air pressure adjustments can be performed automatically via appropriate sensor and control arrangements.

However, the ability to pressure and depressurize the inflatable chamber has created a new problem unique to airspring suspensions. In particular, as air is being removed from the inflatable chamber, the top enclosure element begins to move toward the bottom enclosure element of the airspring, and the flexible sidewall of the container has a tendency to collapse inwardly on itself. Such collapse can result in pinching of the flexible material of the sidewall, which eventually can result in wear and tear, leading to perforation or other damage to the airbag.

Accordingly, it would be desirable to provide an improved airspring design which restricts inward collapse of the flexible sidewall, thus preventing damage to and prolonging the useful life of the airspring assembly. Moreover, it would be desirable to provide a method whereby the improvement can easily be added to existing airspring designs.

SUMMARY OF THE INVENTION

The present invention claims an airspring that is comprised of a first end member, a second end member, a flexible sidewall, and a substantially non-load-bearing collapsible member having an arc-shaped coil. The first end member, the second end member, and the flexible sidewall form the chamber that contains the collapsible member having an arc-shaped coil. The collapsible member substantially restricts the inward movement of the flexible sidewall when the chamber contracts.

The present invention also claims a method for manufacturing an airspring assembly that comprises assembling an airspring chamber, inserting a substantially non-load-bearing collapsible member having an arc-shaped coil into the chamber, attaching the collapsible member to the lower enclosure, and attaching the collapsible member to the upper enclosure. The collapsible member substantially restricts the inward movement of the flexible sidewall when the chamber contracts.

The present invention also claims an airspring that is comprised of a first end member, a second end member, a flexible sidewall, and a substantially non-load-bearing telescopic member comprising two or more telescopic components. The first end member, the second end member, and the flexible sidewall form the chamber that contains the telescopic member. The telescopic member substantially restricts the inward movement of the flexible sidewall when the chamber contracts.

The present invention also claims a method for manufacturing an airspring assembly that comprises assembling an airspring chamber, inserting a substantially non-load-bearing telescopic member comprising two or more telescopic components, attaching the telescopic member to the lower enclosure, and attaching the telescopic member to the upper enclosure. The telescopic member substantially restricts the inward movement of the flexible sidewall when the chamber contracts.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.

DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a cross-sectional view of an embodiment of a rolling lobe or sleeve-type airspring having an exemplary sidewall support member.

FIG. 2 is a cross-sectional view of the airspring of FIG. 1 when fully pressurized.

FIG. 3 is a cross-sectional view of the airspring of FIG. 2 when fully depressurized.

FIG. 4 is a cross-sectional view of another example of an airspring embodiment when fully depressurized.

FIG. 5 is a cross-sectional view of a fully pressurized airspring with a sidewall support member with an arc-shaped coil.

FIG. 6A is a cross-sectional view of the airspring of FIG. 5 when it is fully depressurized.

FIG. 6B is a cross-sectional view of another example of an airspring embodiment when fully depressurized.

FIG. 7 is a cross-sectional view of an airspring embodiment with a sidewall support member with an arc-shaped coil that has a reverse hourglass configuration.

FIG. 8A is a cross-sectional view of the airspring of FIG. 7 when it is fully depressurized.

FIG. 8B is a cross-sectional view of another example of an airspring embodiment when fully depressurized.

FIG. 9 is a cross-sectional view of a pressurized airspring with a telescopic sidewall support member.

DETAILED DESCRIPTION OF THE INVENTION

For ease of reference, the following description will be made with reference to a rolling lobe or sleeve-type airspring. However, it should be understood that the invention is applicable to any type of airspring, such as a single-convoluted airspring, which may be prone to sidewall damage when depressurization occurs.

An exemplary application of the improvement to an airspring is illustrated in FIG. 1, which shows a cross-sectional view of a sleeve-type or rolling lobe airspring 10 appropriate for use in a vehicle suspension system. The airspring 10 includes a flexible, sleeve-like member 12 made of fabric-reinforced rubber that defines a sidewall 14 of an inflatable or pressurizable chamber or container 16. Each end of the container 16 is closed by an enclosure element. For example, in the embodiment illustrated in FIG. 1, the uppermost end of the container 16 is enclosed by an upper enclosure element 18, such as a bead plate, which is attached to the flexible member 12 by rolling and crimping. A lower enclosure element 20 is attached to the lower end of the flexible member 12. For example, as shown in FIG. 1, the lower element 20 may be configured as a cup-shaped enclosure member, which may be integrally molded to the flexible member 12. In alternative configurations, such as convoluted-type airsprings, the lower enclosure element 20 may be a bead plate rolled and crimped to the flexible member 12.

In the embodiment illustrated, the cup-shaped member 20 is coupled to a piston 22, which is a shaped, metal or plastic component configured to both support and provide a surface on which the flexible member 12 can roll. The cup-shaped member 20 may be attached to the piston 22 by an appropriate attachment element (e.g., a bolt 30). Alternatively, member 20 and piston 22 may be an integral component. For example, piston 22 may be shaped such that it includes a concave or cup-shaped portion. The piston 22 also includes appropriate mounting elements, such as tapped holes 24, to secure the airspring 10 to a lower mounting surface, such as the vehicle axle (not shown). Alternatively, in embodiments which do not include a piston 22, the cup-shaped member 20 or other lower enclosure element (e.g., a bead plate) may include appropriate mounting elements.

An air supply component 26 providing for ingress and egress of air to pressurize and depressurize the container 16, respectively, is coupled to the upper enclosure element 18. The upper enclosure element 18 also may include appropriate mounting elements (not shown) for attaching the upper end of the airspring 10 to a mounting surface (e.g., the vehicle chassis) or, alternatively, may be attached to a mounting plate (not shown) having the appropriate mounting elements.

In the embodiment illustrated in FIG. 1, the airspring 10 also includes a “bumper” 28 that protrudes upwardly within the container 16 from the lower enclosure member 20. The bumper 28, which is shown attached to the member 20 and the piston 22 via a bolt 30, typically is made of rubber, plastic, or a fabric-reinforced rubber material and is configured to support the vehicle when the airspring 10 is depressurized, such as when the vehicle is not in use or in the event of a failure while on the road. When the container 16 is depressurized, the sidewall 14 collapses and rolls over the piston 22 until the upper enclosure member 18 contacts the bumper 20. In alternative embodiments, the bumper 28 may be omitted or may have a lower height. If such is the case, then when the container 16 is depressurized and the sidewall 14 collapses, the upper enclosure member 18 will move downwardly until it contacts the lower enclosure member 20.

Airsprings, such as the airspring 10 described in the foregoing paragraphs, are readily available from multiple manufacturers, including Goodyear and Firestone. The flexible member 12 of such airsprings, however, is prone to damage resulting from the tendency of the sidewall 14 to collapse inwardly toward a longitudinal axis 32 of the container 16 as depressurization occurs. Repeated pinching of the flexible member 12 eventually may lead to perforations which prevent pressurization of the container 16. When such failures occur, the entire airspring 10 must be removed and replaced.

These types of failures can be prevented by providing a collapsible sidewall support member 34 as shown in FIG. 1. In the illustrated embodiment, support member 34 is configured as a helical coil. The upper end of the support member 34 is shown attached to the upper enclosure member 18 via a hook-like tab 36, but may readily be attached by any other suitable attachment element. The lower end of the support member 34 is positioned over the bumper 28 and may rest within the cup-shaped lower enclosure member 20. In embodiments which do not include the bumper 28, the lower end of the support member 34 may simply rest within or on the lower enclosure member 20, or, alternatively, may be attached to the lower enclosure member 20 by any appropriate means.

The support member 34 has elastic properties, such that it is both extendible and collapsible along the longitudinal axis 32 as the container 16 is pressurized and depressurized, respectively. At the same time, the support member 34 is configured to maintain a substantially rigid outer perimeter such that it can resist lateral movement of the sidewall 14 toward the longitudinal axis 32 as the container 16 is depressurized. In one example, the support member 34 is not suitable for supporting any type of load; rather, all load-bearing functions are provided by the air pressure within the container 16. Indeed, it is preferable to configure the support member 34 such that it extends and collapses without interfering with the full stroke range of the airspring 10.

The full stroke range of the airspring 10 may be seen with reference to FIGS. 2 and 3. In FIG. 2, the container 16 is fully pressurized such that the upper enclosure member 18 is displaced from the lower enclosure member 20 along the longitudinal axis 32, and the flexible member 12 is in a fully extended position. In FIG. 3, the container 16 is completely depressurized such that the upper enclosure member 18 is in contact with the bumper 28, and the flexible member 12 has rolled along the outer surface of the piston 22.

In the embodiment illustrated in FIGS. 1-3, the sidewall support member 34 has portions with varying diameters. An upper end portion 38 and a lower end portion 40 of the support member 34 have several coils all having the substantially the same diameter and sized to fit against the upper and lower enclosure members 18 and 20, respectively. The primary support for the sidewall 14 is provided by a central portion 42 of the support member 34. Thus, the diameter of the central portion 42 preferably is as large as practicable to minimize inward collapse of the sidewall 14 as depressurization occurs. Transition portions 44 and 46 of the support member 34 include coils having a graduated diameter. This configuration is particularly advantageous since it permits the portions 44 and 46 to fold up or collapse in a manner that minimizes the height of the support member 34 when in the fully collapsed state.

With reference to the embodiment illustrated in FIG. 3 in which the container 16 is fully depressurized, it can be seen that the sidewall support member 34 does not interfere with the full stroke of the airspring 10. It can further be seen from FIG. 3 that the transition portion 44 is fully collapsed, while the transition portion 46 remains in a partially extended state. In embodiments in which the bumper 28 is omitted or has a height that does not extend above the upper edge 48 of the lower enclosure member 20, the sidewall support member 34 may be configured such that the central portion 42 may fit fully within the cup-shaped lower enclosure member 20, allowing both transition portions 44 and 46 to fully collapse. Such an embodiment is illustrated in FIG. 4.

FIG. 5 shows an embodiment of the invention that has a sidewall support member with an arc-shaped coil 47. The rounded surface of the coil faces towards sidewall 14 of container 16. The coil has an arc-shaped configuration so that the edges of the coil are curved inwards toward longitudinal axis 32, forming a C-shaped arc with respect to a cross section of the coil. This embodiment would be useful to prevent portions of sidewall 14 from potentially being caught in between the individual loops of support member 47 when it is being compressed during depressurization of airspring 10 as the space between individual loops may be limited depending on the number of individual loops used in the design. The smaller the space between the individual loops, the less chance that any portion of sidewall 14 could be caught in between the individual loops of support member with an arc-shaped coil 47. Any such pinching of sidewall 14 could cause damage to the flexible material of sidewall 14, which could in turn that lead to the perforation of flexible member 12. Such a condition would prevent pressurization of container 16, or potentially cause other structural damage to the airspring assembly.

FIG. 6A is a cross-sectional view of the airspring of FIG. 5 when it is depressurized. In FIG. 6A, container 16 is completely depressurized such that the upper enclosure member 18 is in contact with bumper 28. Flexible member 12 has rolled along the outer surface of piston 22. FIG. 6B shows an alternate embodiment that does not include a bumper in which sidewall support member with an arc-shaped coil 47 is configured such that it fully fits within cup-shaped lower enclosure member 20.

The diameter of sidewall support member with an arc-shaped coil 47 may be maximized within container 16 in order to minimize any inward collapse of sidewall 14 when depressurization of airspring 10 occurs. In certain embodiments, such as those shown in FIGS. 6A and 6B, sidewall support member with an arc-shaped coil 47, which generally has a tubular structure with a substantially uniform diameter throughout, may be compressed such that individual loops of the coil will be stacked directly on top of each other when airspring 10 is depressurized. This is acceptable as long as interference with the stroke of airspring 10 is minimized when airspring 10 is in a depressurized state.

The overall height of support member with an arc-shaped coil 47 when it is fully collapsed can be modified by increasing or decreasing the number of loops of the coil. When using such embodiments, fewer loops may be needed to provide effective support for sidewall 14 during depressurization because of the arc-shaped configuration, which provides for a relatively thick loop when compared to a traditional spring configuration. Therefore, the number of loops necessary to provide sufficient structure to achieve the objective of reducing or eliminating pinching of sidewall 14 when airspring 10 is depressurized may be reduced relative to another embodiment of the invention with a different coil design.

As shown in FIG. 7, it may be advantageous in certain embodiments for sidewall support member with an arc-shaped coil 80 to have an overall “reverse hourglass” shape with the central portion of support member 80 having a larger diameter than the diameters of the upper and lower portions of support member 80. Intermediate portions of support member 80 increase in diameter from the upper and lower portions of support member 80 as the transition to the central portion of support member 80 is completed. The “reverse hourglass” shape is used to facilitate the efficient collapse of support member 80 in embodiments where coil binding would otherwise prevent the support member from collapsing to the necessary extent if a substantially uniform diameter were used throughout. In one embodiment, the central portion of support member 80 is as large as practicable to minimize inward collapse of sidewall 14 as airspring 10 is depressurized.

As shown in FIG. 8A, the varying diameters of the loops of support member 80 allow at least some of the loops of the arc-shaped coil to collapse into one another, as opposed to being stacked directly on top of each other, when airspring 10 is depressurized. In this embodiment, the overall height of support member with an arc-shaped coil 80 is minimized when in a collapsed state so that upper enclosure member 18 rests on bumper 28 when airspring 10 is depressurized. As shown in FIG. 8B, in alternative embodiments that do not have a bumper, sidewall support member with an arc-shaped coil 80 is configured such that it fits within the cup-shaped lower enclosure member 20.

FIG. 9 shows a cross-sectional view of an airspring with telescopic sidewall support member 48 in a pressurized state. Telescopic sidewall support member 48 may be comprised of two or more concentric components that slide into each other. These concentric components may be cylindrical but are not limited to any particular shape and may even be polygonal in nature. As shown in the embodiment in FIG. 9, when airspring 10 is in a pressurized state, smallest telescopic component 70 is attached to upper enclosure member 18 while largest telescopic component 76 is attached to lower enclosure member 20. The attachment of telescopic sidewall support member 48 to each of upper enclosure member 18 and lower enclosure member 20 can be accomplished using mechanical components, adhesives, welding, soldering, or any other suitable element or combination of elements designed to secure telescopic sidewall support member 48 to the enclosure. For example, telescopic sidewall support member 48 may be integrally molded into upper enclosure member 18 and/or lower enclosure member 20. Alternatively, metallic or non-metallic fasteners (e.g., screws, rivets, etc.) can be used to securely attach telescopic sidewall support member 48 to the enclosure. To the extent that there are multiple telescopic components, the relative diameters of these components will fall somewhere between smallest telescopic component 70 and largest telescopic component 76. Intermediate components 72/74 will have successively smaller diameters as the components are arranged in the telescopic configuration from the bottom of airspring 10 to the top. Another embodiment uses the inverse of this hierarchy in which the largest telescopic component is attached to upper enclosure member 18 and the smallest telescopic component is attached to lower enclosure member 20.

As shown in FIG. 9, the telescopic components easily slide into each other because of the differences in component diameters. In this embodiment, telescopic components have larger diameter bases 78 at the bottom of the telescopic components and smaller diameter rims 77 at the top of the telescopic components in order to maintain connectivity between telescopic components of dissimilar sizes. For example, smallest telescopic component 70 is attached to upper enclosure member 18 and is also connected to intermediate telescopic component 72. Its connection to telescopic component 72 results from the fact that larger diameter base 78 is too large to break free from smaller diameter rim 77 when airspring 10 is pressurized, thereby ensuring the connection between smallest telescopic component 70 and intermediate telescopic component 72.

The illustration in FIG. 9 shows airspring 10 in a pressurized state with telescopic sidewall support member 48 fully extended. Telescopic support member 48 is a substantially non-load-bearing component of the invention and its primary purpose is to reduce or eliminate any pinching of sidewall 14 that may normally occur when the airspring is depressurized in the absence of telescopic sidewall support member 48. Due to the relatively low friction between telescopic components, as airspring 10 is depressurized, telescopic components will slide into each other until airspring 10 is in its fully depressurized state. Even then, the overall height of the telescopic components, which have now been collapsed into one another, is such that collapsed telescopic sidewall support member 48 does not bear any significant load. When optional bumper 28 is incorporated into the system, as with the illustrated embodiment, the overall height of the collapsed telescopic components is less than the height of bumper 28, which limits the descent of upper enclosure member 18.

It should be apparent from the foregoing discussion that any of a variety of configurations of the collapsible sidewall support members are contemplated. That is, the support members can be configured as any type of elastic or collapsible member that minimizes inward collapse of at least portions of the sidewall, while minimally interfering with the full stroke of the airspring. Thus, for example, the support members may have a uniform diameter provided that, when in the fully collapsed state, interference with the stroke of the airspring 10 is minimized. Further, the support members need not have a circular outer perimeter, but may be configured in other manners such that at least a portion of the periphery presents a rigid barrier that minimizes inward collapse of portions of the sidewall. Still further, the support members may be made of any of a variety of materials, such as metallic materials, polymers, or plastics, which are suitably rigid to resist inward collapse of the sidewall.

It should further be apparent from the foregoing discussion that the existing designs of airsprings easily may incorporate an embodiment of a sidewall support member and that already-assembled airsprings may be retrofitted with the improvement. For example, as shown with reference to FIG. 1, incorporation of a sidewall support member into an existing assembly process may entail providing the upper enclosure member 18 with an attachment element, such as the hook-like tab 36, attaching the upper end of the member 34 to the hook 36, positioning the support member 34 within the container 16, and then securing the upper enclosure member 18 to the flexible member 12. Similarly, in some embodiments, already-assembled airsprings may be removed from the shelf or detached from the vehicle chassis and axle, the upper enclosure member 18 removed, and the support member 34 positioned within the container 16 and attached to the existing or a replacement upper enclosure member 18 as described above. The upper enclosure member 18 can be reattached to the flexible member 12 in the conventional manner. The completed assembly 10 then may be replaced on the shelf or re-attached to the vehicle chassis and axle for immediate use.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. 

1. An airspring, comprising: a first end member; a second end member; a flexible sidewall disposed between said first end member and said second end member to define a chamber therebetween having a longitudinal axis, said chamber configured to expand and contract generally along said longitudinal axis; and a substantially non-load-bearing collapsible member having an arc-shaped coil, said collapsible member disposed within said chamber and displaceable between an extended state and a collapsed state responsive to expansion and contraction of the chamber; wherein said collapsible member having an arc-shaped coil is configured to substantially restrict movement of said flexible sidewall toward said longitudinal axis when said chamber contracts.
 2. The airspring of claim 1 wherein said collapsible member having an arc-shaped coil has a substantially uniform diameter within said chamber.
 3. The airspring of claim 1 wherein said collapsible member having an arc-shaped coil has a reverse hourglass configuration.
 4. The airspring of claim 1 wherein said collapsible member having an arc-shaped coil is made of a metallic material.
 5. The airspring of claim 1 wherein said collapsible member having an arc-shaped coil is made of a non-metallic material.
 6. The airspring of claim 1 wherein said collapsible member having an arc-shaped coil is longitudinally extendible while retaining a substantially rigid lateral perimeter.
 7. The airspring of claim 1 wherein said collapsible member having an arc-shaped coil is configured such that when said chamber is fully contracted, said second end member supports said first end member.
 8. The airspring of claim 7 wherein said second end member has a recessed portion and said collapsible member having an arc-shaped coil is configured such that it fits within said recessed portion when said collapsible member is substantially collapsed.
 9. The airspring of claim 1 wherein said collapsible member is attached to said first end member and said second end member.
 10. The airspring of claim 1 further comprising a bumper mounted to said second end member, said bumper supporting said first end member when said chamber is fully contracted.
 11. The airspring of claim 10 wherein said bumper is made of a non-metallic material.
 12. The airspring of claim 10 wherein the height of said bumper is greater than the height of said collapsible member having an arc-shaped coil when substantially collapsed.
 13. The airspring of claim 10 wherein the diameter of said bumper is smaller than the diameter of said collapsible member having an arc-shaped coil.
 14. The airspring of claim 10 wherein said bumper is mounted within said collapsible member having an arc-shaped coil.
 15. A method for manufacturing an airspring assembly, said method comprising the steps of: assembling an airspring chamber, said chamber comprising: an upper enclosure member, a lower enclosure member, and a flexible sidewall; wherein said flexible sidewall is disposed between said upper enclosure member and said lower enclosure member to define said chamber therebetween having a longitudinal axis and wherein said flexible sidewall is configured to expand and retract generally along said longitudinal axis between said upper enclosure member and said lower enclosure member; inserting a substantially non-load-bearing collapsible member having an arc-shaped coil into said chamber wherein said collapsible member having an arc-shaped coil is displaceable between an extended state and a collapsed state responsive to expansion and contraction of said chamber and wherein said collapsible member having an arc-shaped coil is configured to substantially restrict movement of said flexible sidewall toward said longitudinal axis when said chamber contracts; attaching first end of said collapsible member having an arc-shaped coil to said lower enclosure member; and attaching second end of said collapsible member having an arc-shaped coil to said upper enclosure member.
 16. The method of claim 15 wherein said collapsible member having an arc-shaped coil has a substantially uniform diameter within said chamber.
 17. The method of claim 15 wherein said collapsible member having an arc-shaped coil has a reverse hourglass configuration.
 18. The method of claim 15 wherein said collapsible member having an arc-shaped coil is made of a metallic material.
 19. The method of claim 15 wherein said collapsible member having an arc-shaped coil is made of a non-metallic material.
 20. The method of claim 15 wherein said collapsible member having an arc-shaped coil is longitudinally extendible while retaining a substantially rigid lateral perimeter.
 21. The method of claim 15 further comprising the step of mounting a bumper to said lower enclosure member.
 22. The method of claim 21 wherein said bumper supports said upper enclosure member when said chamber is fully contracted.
 23. The method of claim 21 wherein said bumper is made of a non-metallic material.
 24. The method of claim 21 wherein the height of said bumper is greater than the height of said collapsible member having an arc-shaped coil when substantially collapsed.
 25. The method of claim 21 wherein the diameter of said bumper is smaller than the diameter of said collapsible member having an arc-shaped coil.
 26. The method of claim 21 wherein said bumper is mounted within said collapsible member having an arc-shaped coil.
 27. The method of claim 15 further comprising sealing said chamber so as to make it substantially airtight.
 28. An airspring, comprising: a first end member; a second end member; a flexible sidewall disposed between said first end member and said second end member to define a chamber therebetween having a longitudinal axis, said chamber configured to expand and contract generally along said longitudinal axis; and a substantially non-load-bearing telescopic member comprising two or more telescopic components, said telescopic member disposed within said chamber and displaceable between an extended state and a collapsed state responsive to expansion and contraction of the chamber; wherein said telescopic member is configured to substantially restrict movement of said flexible sidewall toward said longitudinal axis when said chamber contracts.
 29. The airspring of claim 28 wherein said telescopic member comprises three or more telescopic components.
 30. The airspring of claim 28 wherein said telescopic member comprises four or more telescopic components.
 31. The airspring of claim 28 wherein said telescopic member is made of a metallic material.
 32. The airspring of claim 28 wherein said telescopic member is made of a non-metallic material.
 33. The airspring of claim 28 wherein said telescopic member is longitudinally extendible while retaining a substantially rigid lateral perimeter.
 34. The airspring of claim 28 wherein said telescopic member is configured such that when said chamber is fully contracted, said second end member supports said first end member.
 35. The airspring of claim 34 wherein said second end member has a recessed portion and said telescopic member is configured such that it fits within said recessed portion when said telescopic member is substantially collapsed.
 36. The airspring of claim 28 wherein said telescopic member is attached to said first end member and said second end member.
 37. The airspring of claim 28 further comprising a bumper mounted to said second end member, said bumper supporting said first end member when said chamber is fully contracted.
 38. The airspring of claim 37 wherein said bumper is made of a non-metallic material.
 39. The airspring of claim 37 wherein the height of said bumper is greater than the height of said telescopic member when substantially collapsed.
 40. The airspring of claim 37 wherein the diameter of said bumper is smaller than the diameter of said telescopic member.
 41. The airspring of claim 37 wherein said bumper is mounted within said telescopic member.
 42. A method for manufacturing an airspring assembly, said method comprising the steps of: assembling an airspring chamber, said chamber comprising: an upper enclosure member, a lower enclosure member, and a flexible sidewall; wherein said flexible sidewall is disposed between said upper enclosure member and said lower enclosure member to define said chamber therebetween having a longitudinal axis and wherein said flexible sidewall is configured to expand and retract generally along said longitudinal axis between said upper enclosure member and said lower enclosure member; inserting a substantially non-load-bearing telescopic member comprising two or more telescopic components into said chamber wherein said telescopic member is displaceable between an extended state and a collapsed state responsive to expansion and contraction of said chamber and wherein said telescopic member is configured to substantially restrict movement of said flexible sidewall toward said longitudinal axis when said chamber contracts; attaching bottommost telescopic component of said telescopic member to said lower enclosure member; and attaching topmost telescopic component of said telescopic member to said upper enclosure member.
 43. The method of claim 42 wherein said telescopic member comprises three or more telescopic components.
 44. The method of claim 42 wherein said telescopic member comprises four or more telescopic components.
 45. The method of claim 42 wherein said telescopic member is made of a metallic material.
 46. The method of claim 42 wherein said telescopic member is made of a non-metallic material.
 47. The method of claim 42 wherein said telescopic member is longitudinally extendible while retaining a substantially rigid lateral perimeter.
 48. The method of claim 42 further comprising the step of mounting a bumper to said lower enclosure member.
 49. The method of claim 48 wherein said bumper supports said upper enclosure member when said chamber is fully contracted.
 50. The method of claim 48 wherein said bumper is made of a non-metallic material.
 51. The method of claim 48 wherein the height of said bumper is greater than the height of said telescopic member when substantially collapsed.
 52. The method of claim 48 wherein the diameter of said bumper is smaller than the diameter of said telescopic member.
 53. The method of claim 48 wherein said bumper is mounted within said telescopic member.
 54. The method of claim 42 further comprising sealing said chamber so as to make it substantially airtight. 